Lupus is of two types. 1) The discoid lupus that is inflammation of skin 2) systemic lupus erythmatosus (SLE) causes inflammation of internal organs. One of the symptoms of SLE is butterfly rash. This occur on nose and its both side and looks like butterfly. The psoriasis is another skin disease of unknown etiology, which cause itching and redness on face and skull. Both diseases are not linked. The difference between SLE and psoriasis is that silvery plaques characterize psoriasis while SLE does not.